Gas turbine engines generally include a gas generator with a compressor section for compressing air flowing through the engine, a combustor in which fuel is mixed with the compressed air and ignited to form a high energy gas stream, and a turbine section for driving the compressor. Many engines further include an additional turbine section located aft of the gas generator which drives a fan or propeller. In such engines, each of the turbines and compressor includes one or more bladed rows. Each bladed row includes individual blades mounted in a blade support structure as a rotor disk or casing.
Numerous blading configurations are known for mounting blades within such support structures. These configurations may be broadly classified into axially loaded blades and circumferentially loaded blades. Axially loaded blades typically include a platform and/or root portion at the base of the blade which is inserted and retained by a mating axial slot in the support structure. Circumferentially loaded blades typically include a platform and/or root which is inserted into and retained by a circumferential recess in the support structure.
Unlike axially loaded blades, circumferentially loaded blades generally contact each other within the circumferential recess. When such blades are subjected to the forces associated with the flow stream in the turbomachine, axial, tangential, and twisting moment forces are reacted between the blade platform and support structure and between adjacent blade platforms.
In prior art configurations, the platforms of circumferentially loaded blades contact adjacent blade platforms over a relatively broad surface area. Unless very small tolerances are maintained in machining the contact surfaces between such blades, non-uniform, concentrated loading between the blade platform and support structure and between adjacent blade platforms may occur. This concentrated loading may result in uneven wear and may necessitate premature removal and replacement of the blades as well as decreased operating efficiency caused by loose blades.